Back to: MICROBIOLOGY 400 LEVEL
Welcome to class!
Hello, bright mind! It’s always great to see your enthusiasm for learning. Today, we’re going to talk about something you use every day—water. But not just any kind of water—we’ll be focusing on Potable Water Standards. Have you ever wondered what makes water safe enough to drink? Whether it’s from a sachet, borehole, or tap, not all water is safe unless it meets the right standards. Let’s learn what those standards are and why they matter so much.
Potable Water Standards
Potable water simply means water that is safe for drinking and domestic use, like cooking and bathing. For water to be considered potable, it must meet specific standards set by health and environmental authorities, such as the World Health Organization (WHO) and Nigeria’s Standard Organisation of Nigeria (SON).
These standards are guidelines that show what physical, chemical, and biological properties the water must have (or not have) to be safe for human consumption.
1. Physical Standards
These include the characteristics you can see, smell, or taste in water:
Colour: Drinking water should be colourless.
Taste and odour: It should have no offensive taste or smell.
Turbidity (cloudiness): Clear water is ideal. High turbidity may mean there are suspended particles that could carry microbes.
2. Chemical Standards
Chemicals can enter water through pollution, pipes, or natural deposits in the soil. Standards are set to control harmful chemicals:
pH: Safe water should have a pH between 6.5 and 8.5—not too acidic or too alkaline.
Chlorine: If used for disinfection, it must not exceed 5 mg/L.
Nitrates: Should not be more than 50 mg/L as high levels can harm infants.
Heavy Metals: Elements like lead, mercury, arsenic, and cadmium must be in extremely low amounts or completely absent.
3. Biological Standards
The most dangerous water pollutants are microscopic and invisible:
E. coli and other coliforms: Must not be present at all in potable water.
The presence of these indicates faecal contamination and a high risk of diseases like cholera and typhoid.
Why Standards Matter in Nigeria
In many Nigerian communities, people depend on wells, boreholes, or rivers. If these sources are not treated or tested regularly, they may carry diseases. Potable water standards help water agencies, sachet water companies, and communities know when water is safe or needs treatment.
Summary
- Potable water is water that is safe to drink and use.
- It must meet physical, chemical, and biological standards.
- Physically, water must be clear, colourless, and without bad odour or taste.
- Chemically, water must have a safe pH, and low levels of chlorine, nitrates, and no dangerous metals.
- Biologically, water must be free of harmful microbes like E. coli and coliforms.
- WHO and SON provide the guidelines for potable water in Nigeria.
- These standards help protect public health.
- Unsafe drinking water can lead to diseases like diarrhoea and cholera.
- Monitoring and treating water ensures safety in homes, schools, and hospitals.
Evaluation
- What is the meaning of potable water?
- Mention two physical and two chemical standards for potable water.
- Why must potable water be free of E. coli?
You’re not just learning facts—you’re gaining knowledge that can improve the lives of families and communities. Your dedication makes you a future leader in public health and environmental safety. Keep going strong with Afrilearn—we can’t wait to see what you achieve next. See you in the next class!